Dental syringe tip and syringe holder therefor

ABSTRACT

This disclosure is directed to a dental syringe and a disposable syringe tip for use therewith, and more particularly to an improved syringe tip constructed to minimize the entrainment of air by the material being extruded and to provide a dentist with a maximum of visibility during use. The syringe tip includes a cylindrical body portion to define a reservoir that is provided with a conically shaped, closed front end and a full opening at the other end, which is adapted to be sealed by a displaceable piston. The closed front end is provided with an internal frusto-conical chamber disposed in communication with an angularly offset discharge nozzle having its passageway at the inner end thereof disposed contiguous to the blunt end of the internally disposed frusto-conical chamber; and the disposable piston having a frusto-conical end portion to complement the shape of the internal front end of the syringe tip to enhance the complete evacuation of the material disposed within the syringe tip without the entrainment of any air.

FIELD OF INVENTION

This invention relates to a dental syringe device, and more particularlyto an improved syringe tip for use with a syringe holder of the typeutilized to facilitate the placement of various dental materials in oron a tooth, such as composite dental filling materials, bondingmaterials, sealants, etchants and the like.

RELATED APPLICATIONS

This application relates to a design application S.N. 07/306,651 filedFeb. 6, 1989 for Dental Syringe Tip.

PROBLEM AND PRIOR ART

Dental syringes and syringe tips for use therewith have been known forsome years. Such a dental syringe was initially disclosed in my U.S.Pat. No. 3,581,399. Other variations of such dental syringes anddisposable syringe tips and capsules have been made the subject of otherpatents granted to me as evidenced by U.S. Pat. Nos. 3,900,954;4.198,756; 4,682,950; 4,768,954; DES 289,682 and DES 292 825. Patentsdirected to similar dental syringes and disposable capsules for usetherewith have also been granted.. together as, evidenced by U.S. Pat.Nos. 4,295,828; 4,330,280; 4,384,853; 4,391,590 and 4,767,326.

In utilizing syringe tips of the configuration disclosed in U.S. Pat.Nos. 4,330,280; 4,384,853: 4,391,590 and 4,767,326, which arecharacterized by a common and well known hemispherical end wallstructure with off-set discharge nozzle, it has been noted that in thefilling of such syringe tip with a viscous material, there is a tendencyto entrap air in the bulbous hemispherical end portion, and that the airtends to remain entrapped therein only to become entrained within thematerial as it is dispensed from the syringe tip upon the ejectionthereof. The dental material that is generally dispensed by suchcapsules or syringe tip comprises a viscous composite resin dentalfilling material and the entrapment of any air within such material isconsidered to be highly detrimental to any tooth restoration madethereby. This is because the entrapment of any air in such compositeresin filling material will result in voids being formed in therestoration, and which voids weaken and/or cause premature failure.

In restoring a tooth with a composite resin filling material, it istherefore desirable that the entrapment of any air therein be held tothe absolute minimum so as to effect a final restoration that is free ofany air voids. Another problem noted with capsules or syringe tipshaving the bulbous hemispherical front end configuration with the offsetdischarge nozzle of the type disclosed in U.S. Pat. No. 4,391,590 wasthat visibility was obscured when placing the material with such syringetip configuration in deep small areas. This was due to the bulboushemispherical end obscuring the site where the material was to beplaced: as the discharge nipple or orifice through which the materialwas extruded would be obscured thereby.

Also, there has been a growing tendency in the art to formulate dentalcomposite resin filling materials with a heavier or more viscousconsistency. With such heavy bodied materials, it is imperative that thesyringe tips for dispensing such material be made to withstand thetremendous pressures that occur when such viscous materials are to beextruded therefrom. Heretofore, the known capsules, such as disclosed inU.S. Pat. No. 4,391,590 and 4,767,326 were made with a uniform wallthickness throughout, and thus did not compensate for the resistance ofpressure in those areas where the pressures were maximized during anextruding operation; e.g. in the closed end of the capsule or syringetip.

OBJECTS

An object of this invention is to provide an improved syringe tip foruse with a dental syringe having a construction that prohibits theentrapment and/or entrainment of air in the material as it is beingextruded from the syringe tip.

Another object of this invention is to provide an improved syringe tipconstructed so as to allow better visibility for the dentist during thedelivery of the material to a tooth.

Another object of this invention is to provide an improved syringe tiphaving a reinforced front end to better withstand the pressures incurredduring an extruding operation.

Another object of this invention is to provide an improved syringe tipconstruction having an angularly disposed discharge nozzle having itsinlet disposed contiguous to an internal front end wall of the syringetip so as to minimize or prohibit the entrapment of air within thesyringe tip.

SUMMARY OF THE INVENTION

The foregoing objects and other features and advantages are attained byan improved syringe tip construction that comprises a generallycylindrical body portion to define a reservoir for containing apredetermined amount of dental material to be dispensed therefrom. Oneend of the body portion is provided with a full open end through whichit can be readily filled with the dental material to be dispensed, e.g.a composite resin filling material. The other end of the cylindricalbody portion is closed by a conically shaped tip end that tapersinwardly toward the front end of the syringe tip, and which conicallyshaped tip defines an internal frusto-conical chamber disposed in opencommunication with the reservoir and in axial alignment therewith. Thefront end of the internal chamber is provided with a blunt end wall anda discharge nozzle is angularly disposed relative to the conical closedend so that the passageway extending through the discharge nozzle isprovided with an inlet disposed contiguous to the internal blunt frontend wall of the syringe tip. A displaceable piston is provided to sealthe full open end of the body portion, and which piston is provided witha frusto-conical end portion to complement the shape of the internalfrusto-conical chamber at the front end of the syringe tip so as toinsure complete evacuation of the material within the syringe tip freeof any air entrainment. Circumscribing the open end of the body portionis a laterally extending flange: and a sealing cap may be provided toseal the discharge orifice of the angularly disposed nozzle. Theimproved syringe tip is adapted to be used with a syringe constructionhaving a barrel for receiving the syringe tip and having a plunger foreffecting the displacement of the piston for extruding the material outof the syringe tip.

FEATURES

A feature of this invention resides in the provision of an improveddental syringe tip having a cylindrical reservoir portion for containinga predetermined supply of a dental material that is in opencommunication with an axial aligned frusto-conical internal chamberdisposed adjacent an angularly offset discharge nozzle arranged toprohibit entrapment and/or entrainment of air by the material to beextruded therefrom.

Another feature of this invention resides in an improved dental syringetip having a conical tip with an angular offset nozzle for enhancing thevisibility of the dentist in placing of the material being dispensed.

Another feature resides in the provision of an improved dental syringetip in which the front end of the syringe is reinforced to withstand theinduced pressures thereon during an extruding operation.

Another feature resides in the provision of an improved dental syringetip and displaceable piston arranged to insure total evacuation of thematerial to be dispensed thereby.

Other features and advantages will become more readily apparent whenconsidered in view of the drawings and description thereof in which:

FIG. 1 is a side elevation view, shown partly in section of a dentalsyringe and dental syringe tip for use therewith that embodies theinvention.

FIG. 2 is a perspective view of the improved syringe tip.

FIG. 3 is a sectional view of the syringe tip illustrated in FIGS. 1 and2.

FIG. 4 is a detail perspective view of the piston sealing the open endof the syringe tip.

DETAIL DESCRIPTION

Referring to the drawings, FIG. 1 illustrates a dental syringe 10 of atype disclosed in my prior issued U.S. Pat. No. 4,198,756. Such dentalsyringe 10 comprises essentially an elongated barrel 11 having a frontend portion 11A adapted to detachably hold the improved dental syringetip 12, as will be hereinafter described. In the illustrated embodiment,the front end of the barrel 11 is provided with a cut-away portion todefine a breech opening 13 in the upper part of the barrel. The frontportion of the barrel, which is not cut-away, is provided with aninturned flange as indicated at 14 to define an internal shoulder toengage the flange of the syringe tip as will be hereinafter described.Connected to the barrel adjacent the other end thereof is a handle orfinger grip member 15. Pivotably connected to the handle 15 is anactuating lever 16 which is disposed in bearing relationship with aplunger 17 which is slidably disposed within the barrel 11. A springinterposed about the end of the plunger 17 maintains the plunger 17 in anormally retracted position as shown in FIG. 1. The front end of theplunger 17 is provided with a projection 17A arranged to engage thedisplaceable piston of the syringe tip 12, as will be hereinafterdescribed, to effect the extrusion of the material within the syringetip 12 when the lever 16 is actuated.

It will be understood that the front end of the barrel is sized orproportioned so as to frictionally retain the rear portion off thesyringe tip in the notched opening 13 formed therein. As shown, theshoulder or inturned flange 14 engages the flange 12A of the syringe tipto prevent axial displacement of the syringe tip 12 during actuation ofthe syringe 10. The arrangement is such that the syringe tip is forcedinto and held in place by the seat defined at the notched end of thebarrel 10. To achieve a suitable friction fit of the syringe tip in thefront end of the barrel, the cut-out 13 is formed so that thecircumscribing side walls to the barrel extend about the circumferenceof the syringe tip slightly more than 180° .

While the syringe illustrated comprises a so-called "gun type" syringe,it will be understood that other syringe constructions can be utilizedto practice the invention, e.g. such as disclosed in my prior U.S. Pat.Nos. 3,900,954 or 3,581,399.

In accordance with this invention, the improved syringe tip 12 comPrisesa generally cylindrical body portion 12B which is fully open at one endas indicated at 19, and which is provided with a closed end 20 at theother end thereof. As shown, the closed end is generally of a roundconical shape which tapers inwardly toward the closed apex end 21. Thefront conical end 20 is provided with a frusto-conical internal wall 22to define an internal frusto-conical internal chamber 23 which isaxially disposed and in open communication with the reservoir portiondefined by the cylindrical body portion 12B. As best seen in FIG. 3, theinner frusto-conical chamber 23 terminates in a blunt end wall 25. Dueto the roundness of the outer wall surface of the front conical end 20and the angular interior surface 22 of the conical chamber 23, it willbe noted that the wall thickness of the conical front end varies,whereby the thickness of the front end wall progressively increasestoward the medium of the internal frusto-conical chamber. Thearrangement is such that the variable thickness of the syringe tip wallat the front end thereof functions to reinforce the syringe tip so as toresist the pressures which tend to build up on the front end wall as thematerial is being extruded from the syringe tip. As the manufacturers ofdental composite resin materials are producing a more viscous compositeresin, the problem of pressure build-up on the end walls of a syringetip is aggravated. Thus, the described construction renders the syringetip 12 compatible for use with the most viscous of known dentalcomposite resin materials.

Formed as an integral part of the syringe tip is a discharge nozzle 26which is angularly disposed relative to the longitudinal axis of thebody portion 12 that defines the reservoir 24 for containing the dentalmaterial M. As shown, the nozzle 26 is provided with a passageway 27that is disposed in communication with the internal conical chamberportion 23. The angulation of the passageway is such that its inlet end27A is disposed immediately adjacent the blunt end wall 25, so that noportion of the frusto-conical chamber 23 extends forwardly of the inlet27A of the nozzle passageway 27 that can form a pocket to entrap airwhich would ultimately be entrained in the material being extruded.

In accordance with this invention, the open end 19 of the body portionis sealed by a displaceable piston 28. In the illustrated embodiment,the piston 28 includes a rear cylindrical portion 28A sized to beslidably received within the body of the syringe tip and a connectedfrusto-conical tip portion 28B. The frusto-conical tip 28B of the pistonis sized so as to closely conform to the shape of the internal conicalchamber 23 so as to insure maximum evacuation of the material M disposedwithin the syringe tip. At the base portion of the piston tip 28B, thepiston 28 may be provided with one or more circumscribing ribs or wipers28C to provide a positive seal between the piston 28 and the internalwall of the syringe tip so as to prevent any back flow of the material Mduring an extruding operation.

Preferably, the syringe tip described is formed of a molded plasticmaterial which may comprise 101 Zytel nylon, or other suitable plasticmaterials such as polypropolene, etc., depending upon the nature of thematerial to be extruded therefrom.

The syringe tip may also be suitably colored so as to identify the typeof material contained therein or be rendered light resistant or lightopaque for use with light activated materials which are currently invogue. Also, the syringe tips may be preloaded with suitable materialsand sealed by means of an end cap 29 placed over the discharge orificedefined by the nozzle 26.

Loading of the syringe tip 12 described can be readily effected byinserting the material through the full open end 19 thereof. With theconstruction described, it will be apparent that any air confined withinthe syringe tip during a loading operation will be vented or forced outof the nozzle tip 26, and no entrapment of air can occur when thesyringe tip is fully loaded. In the event the syringe tip is onlypartically loaded with dental material M, any air disposed between thematerial and the front end of the tip will be evacuated before thematerial begins to extrude. Thus, there are no entrapped air pockets bywhich air can be entrained in the dental material during an extrusionoperation.

The conical shaped tip as described further enhances the visibility forthe dentist when delivering the composite material to a tooth; as thedischarge nozzle is not obscured. Also, since dentists inherently haveto work in very close or small areas, the conical tip configurationprovides better access as well as better visibility in such situations.The trucated or frusto-conical internal chamber at the closed end of thesyringe tip further allows better direction in funneling the material tobe extruded toward the discharge nozzle, thereby minimizing theresistive forces that occur with very viscous type materials.

While the invention has been described with respect to a particularembodiment thereof, variations and modifications may be made withoutdeparting from the spirit or scope of the invention.

What is claimed is:
 1. A syringe tip for use in a dental syringe for theplacement of a predetermined amount of a viscous dental composite resinfilling material in a tooth to form a tooth restoration comprisinga bodyportion having a generally cylindrical shape to define a reservoirportion for containing a predetermined amount of dental fillingmaterial. said body portion having an opening co-extensive to thecylindrical shape of said reservoir portion at one end thereof, alaterally extending flange circumscribing said opening, and said bodyportion having a tapering closed end at the other end thereof disposedin axial alignment with the axis of said body portion, said taperingclosed end having an internal conically shaped wall surface taperingtoward said closed end terminating in a blunt internal end wall, saidinternal conically shaped wall surface defining an internal frustroconical chamber being disposed in open communication with and forming acontinuation of said reservoir portion, and a discharge nozzle angularlydisposed relative to said closed end, said discharge nozzle including apassageway through which the material contained in said internal frustroconical chamber and reservoir portion is adapted to be extruded, and adisplaceable piston for sealing the open end of said reservoir portion;said displaceable piston having a conical front end complementing saidinternal conically shaped wall surface.
 2. A syringe tip as defined inclaim 1 wherein said passageway includes an inlet end and an outlet end,said inlet end being disposed immediately adjacent said blunt internalend wall.
 3. A syringe tip for use in a dental syringe for the placementof a dental composite resin filling material for forming a toothrestoration comprisinga body portion having a cylindrical configurationdefining a reservoir portion, said body portion having an opening formedat one end that is substantially co-extensive to the diameter of saidreservoir portion, a laterally extending flange circumscribing saidopening formed at one end, and said body portion being closed at theother end thereof, said closed end having an internal tapering wallco-axially disposed with said reservoir portion, and terminating in ablunt internal end wall to define an internal frustro-conical chamberaxially disposed and in open communication with said reservoir portion,a discharge nozzle angularly disposed relative to said closed end, saiddischarge nozzle including a passageway disposed in communication withsaid closed end, said passageway having an inlet end disposed contiguousto said blunt end wall, and a displaceable piston for sealing saidopening, said displaceable piston including a cylindrical rear portionand a conical front portion, said conical front portion complementingthe conical shape of said internal surface of said closed end.
 4. Asyringe tip for use in a dental syringe for the placement of a dentalfilling material comprisinga body portion having a cylindricalconfiguration defining a reservoir portion, said body portion having anopening formed at one end that is substantially co-extensive to thediameter of said reservoir portion, and said body portion being closedat the other end thereof, said closed end having an internal taperingwall co-axially disposed with said reservoir portion, said closed endterminating in a blunt internal end wall, a discharge nozzle angularlydisposed relative to said closed end, said discharge nozzle including apassageway disposed in communication with said closed end, saidpassageway having an inlet end disposed contiguous to said blunt end,and a displaceable piston or sealing said opening, wherein saiddispalceable piston includes a cylindrical rear portion and a conicalfront portion, said conical front portion complementing the conicalshape of said internal surface of said closed end.
 5. A syringe tip asdefined in claim 4 wherein said closed end has an outer wall surfacethat tapers inwardly.
 6. A syringe tip as defined in claim 5 wherein thethickness between the inner and outer surfaces of said closed endvaries.
 7. A syringe tip as defined in claim 6 wherein the thickness ofthe closed end progressively increases toward the medium portionthereof.
 8. A syringe tip as defined in claim 4 and including acircumscribing wiper on said displaceable piston.
 9. A syringe tip asdefined in claim 8 wherein said wiper is disposed between said rearportion and front portion of said piston.
 10. A syringe tip for use witha dental syringe for the placement of a predetermined amount of a dentalmaterial in a tooth comprisinga body portion having a generallycylindrical shape to define a reservoir portion for containing apredetermined amount of a dental material, and said body portionterminating in a closed end portion that tapers inwardly toward saidclosed end thereof, said closed end portion defining an internalconically shaped chamber axially disposed relative to said reservoirportion, said conically shaped internal chamber tapering inward towardsaid closed end to define an inner blunt end wall surface disposednormal to the axis of said reservoir portion, a discharge nozzleangularly disposed relative to said closed end, said discharge nozzlehaving a passageway disposed in communication with said closed end, saidpassageway having an inlet disposed contiguous to said blunt end wall,said body being open at its other end, and a displaceable piston forsealing the open end, said displaceable piston having a frusto conicaltip end to complement the internal chamber of said closed end.
 11. Asyringe tip for use in a dental syringe for the placement of a dentalmaterial in or on a tooth comprisinga syringe body having a cylindricalshape to define a reservoir portion, said syringe body having a fullopening at one end thereof, and a tapering sealed end at the other endthereof, a laterally extending flange circumscribing said full opening,said tapering sealed end having an exterior rounded conical surface anda conical interior surface to define an internal conically shapedchamber disposed in axial alignment with said reservoir portion, saidinternal conically shaped chamber tapering inwardly toward said sealedend, and terminating in a blunt end wall, a pre-determined amount ofdental material disposed in said reservoir portion, a discharge nozzleangularly disposed relative to said sealed end, said nozzle having apassageway extending therethrough, said passageway having an inlet enddisposed in communication with said conically shaped chamber andcontiguously disposed to said blunt end whereby the plane of said bluntend forms a juncture with said inlet, a displaceable piston closing saidfull opening to seal said material within said reservoir portion, saidpiston including a frusto-conical tip complementing the shape of saidinternal conical chamber so as to insure maximum evacuation of saidmaterial upon the displacement of said piston, and a sealing cap fittedover the end of said discharge nozzle.